Among stacked piezoelectric actuators, the laminated piezoelectric element described in Japanese Patent Laid-open No. 2005-108989 (Patent Literature 1) is known. This laminated piezoelectric element has a laminate constituted by laminating piezoelectric ceramic layers and internal electrode layers, where the internal electrode layers are comprised of first internal electrode layers and second internal electrode layers. The first internal electrode layers are led out alternately to different sides of the laminate. The second internal electrode layers are formed over roughly the entire cross-section of the laminate for each specified length dimension in the laminating direction of the laminate, and led out at least to one side of the laminate. Provided at the top and bottom of this laminated piezoelectric element are protective layers that serve as points of contact with the target object to be driven. With this type of laminated piezoelectric element, electric field is first applied between the second internal electrode layers to achieve overall polarization whereby the domain direction of the laminate as a whole is oriented roughly to the laminating direction, after which electric field is applied to the laminate via the first internal electrode layers to achieve inter-layer polarization.
As another disclosed example, the laminated piezoelectric element described in Japanese Patent Laid-open No. Hei 7-135348 (Patent Literature 2) is known. This laminated piezoelectric element comprises: multiple piezoelectric layers; internal electrodes that are provided between the piezoelectric layers and led out, depending on the polarity, to one of the two opposing side faces; and two external electrodes that each connect to the internal electrodes of the same polarity led out to one of the two side faces, where the two external electrodes are formed in such a way that each electrode covers the side face to which the internal electrodes of the same polarity have been led out, as well as the top side and bottom side of the side face.